This invention relates to apparatus and a method for the removal and treatment of prostate tissue to treat conditions associated with diseases or disorders resulting in obstruction of the uro-genital systems.
As men age, their prostate glands typically enlarge due to growth of intraprostatic paraurethral glands tissue (prostate adenoma) obstructing the flow of urine through the urethra. This condition is known as benign prostatic hypertrophy (xe2x80x9cBPHxe2x80x9d), and results in a partial or total inability to urinate. The incidence of symptomatic BPH for men in their fifties is approximately 50%, rising to 90% by age 85. About 25% of men in the United States will be treated for BPH by age 80.
Traditional surgical therapy for BPH has involved open enucleation or transurethral resection of the prostate. Surgical treatment of BPH is generally reserved for patients with severe symptoms or for those who have developed urinary retention, renal damage caused by BPH, or those with significant potential complications if treatment were withheld. These painful procedures usually result in long-term recovery although the patient may be subjected to traumatic side-effects.
The most common surgical procedure, Transurethral Resection of the Prostate (xe2x80x9cTURPxe2x80x9d), involves the removal of the prostate""s innermost core in order to enlarge the caliber of the prostatic urethra. The average TURP procedure costs approximately $12,000 and requires a hospital stay of approximately 3 to 4 days. During this period the patient is burdened with a Foley drainage catheter and bag. TURP side-effects include impotence (up to 30%), retrograde ejaculation, and short-term or permanent incontinence.
Suprapubic or Retropubic (Open) Prostatectomy (SPP/RPP) involves surgical removal of the enlarged prostate via an incision in the lower abdomen, usually requiring a 5 to 7 day hospital stay. Patients are allowed to return to work 2 to 3 weeks after the surgery. Open prostatectomy may result in impotence (up to 30% of cases), retrograde ejaculation and incontinence.
Transurethral Incision of the Prostate (TUIP) is an endoscopic surgical procedure in which one to three cuts is made in the prostate to relax the constriction on the prostatic urethra. TUIP is limited to prostates below 30 grams in size and requires 2 days of hospitalization. TUIP patients may experience short-term incontinence, and on rare occasions, retrograde ejaculation.
Transurethral Vaporization of the Prostate (TUVP) is a procedure for ablating the prostatic tissues by vaporization using an electrosurgical roller. The cost and the hospital stay for this procedure is similar to that of the TURP. Although TUVP causes less bleeding than TURP, the impotence rates are not dissimilar.
In balloon dilatation, a catheter with a high-pressure balloon at the end is inserted through the urethra and into the prostatic urethra. The balloon is then inflated to stretch and tear the prostatic urethra and to enlarge its caliber. Clinical studies have demonstrated a high rate of obstructive recurrence. This therapy has largely been abandoned.
Laser assisted Prostatectomy includes two similar procedures, Visual Laser Ablation of the Prostate (V-LAP) and Contact Laser Ablation of the Prostate (C-LAP). Typically, the procedure is performed in the hospital under either general or spinal anesthesia, and at least an overnight hospital stay is required. In V-LAP, the burnt prostatic tissue then necroses, or dies, and over four to twelve weeks is sloughed off during urination. In C-LAP, the prostatic and urethral tissue is burned on contact and vaporized. The major drawbacks to these procedures include their high cost equipment and high re-treatment rates.
TransUrethral Microwave Therapy (TUMT) is based on a catheter inserted into the urethra, on which a microwave antenna is situated at the level of the prostate. The urethra can be spared by cooling, but will otherwise be destroyed. Scarring of the prostatic tissue enlarges the urethral lumen. The drawback of this treatment is long catherization time (1-6 weeks) and high-re-treatment rates.
TransUrethral Needle Ablation (TUNA) is performed by transurethrally inserting two radio-frequency antennas into the prostatic tissue for heat damage creation. The drawbacks involved are a long catheterization period (up to 6 weeks) and very high re-treatment rates. Interstitial Laser Coagulation (ILC) is very similar to TUNA but the heat source is a laser.
High Intensity Focused Ultrasound (HIFU) brings a beam of ultrasound into a tight focus at a selected depth within the prostate, generating temperatures of 80-100xc2x0 C. and causing coagulation necrosis. The energy is delivered transrectally, and a catheter is inserted into the urethra for enhancing the treatment. The drawbacks of this treatment is the major cost of the equipment and long catheterization periods.
Water Induced Thermotherapy (WIT) is similar to non-urethra sparing microwave treatments. The heat damage is created by heating a balloon at the prostatic urethra and by heating the prostatic tissue. It has the same drawbacks as microwave treatments.
Holmium Laser Prostatectomy is comparable to open prostatectomy. During this treatment, as in open surgery, the entire hypertrophied gland is enucleated (but endoscopically) and dropped into the bladder. This gland should be morselated for removal. The drawbacks of this treatment are the cost of the equipment and the long learning curve.
In addition to the above, a few general limitations emerge regarding alternative therapies. By targeting tissue killing to regions surrounding the urethra, some relief of compressive urethral obstruction is achieved. However, with the exception of Holmium Laser Prostatectomy, none of these procedures directly removes material. All of these techniques rely on the body""s response to injury and inflammation (the reticuloendothelial system (RES)) to slowly remove necrotic cells and xe2x80x9cclean-upxe2x80x9d the area. As such, all of these techniques take several months to ultimately lead to a maximal effect, which is also limited. In many of these techniques no actual net tissue removal or reduction occurs. Rather, the injury may lead to localized scarring and fibrosis which may ultimately lead to obstruction recurrence. The response to injury is individually variable and lesser degrees of relief are often achieved. Patients who are treated by thermotherapy typically recover quickly, but need to be catheterized for at least one week post-treatment to maintain urine flow. Even after catheter removal, irritating urinary symptoms frequently persist during the period of tissue sloughing and healing.
Drug therapy is sometimes an option. Some drugs are designed to shrink the prostate by inhibiting or slowing the growth of prostate cells. Other drugs are designed to relax the muscular tissue in the prostate capsule and bladder neck to relieve urethral obstruction. Current drug therapy (including Finasteride Therapy, Alpha Blocker Therapy and Phytotherapy) generally requires daily administration for the duration of the patient""s life, and are known to cause dizziness and fainting, decreases in blood-pressure, impotence, retrograde ejaculation or a reduction in the volume of ejaculated sperm. Furthermore, the effectiveness of these drug therapies in long-term treatment of BPH has not been proven scientifically.
To date, the most effective surgical intervention for BPH, is TURP. This procedure is invasive, requiring regional or general anesthesia, several days of hospitalization and post-treatment placement of a drainage catheter. TURP frequently presents a high operative cost and risk for many patients. The potential disadvantages and limitations of TURP include bleeding, urinary tract infections, urethral irritation, discomfort, occasional urinary incontinence, sexual dysfinction. Despite these limitations, TURP is currently the gold standard of therapy for BPH.
It is therefore an object of the present invention to provide apparatus and materials for treatment of BPH.
It is a further object of the present invention to provide polymeric materials, drugs and biologically active compositions which can be delivered or released within or adjacent to prostatic or urethral tissue to aid in healing. It is another object of the present invention to provide an effective, low cost outpatient BPH treatment with enhanced efficacy, reduced length of hospital stay, reduced patient discomfort, and lower recurrence rate.
Trans Urethral Volume Reduction of the prostate (TUVOR) has been designed with distinct tissue and function sparing objectives that are unavailable in any current therapy. This process allows for significant volume reduction of the prostate as an out-patient therapy, not requiring several days in the hospital with a catheter. There are several key concepts that enable minimal trauma, outpatient therapy for even severely enlarged prostates.
The first concept upon which TUVOR is based is acute tissue removal with reduced tissue trauma. The approach is to achieve clean surgical excision of BPH tissue (adenoma) with reduced urethral and sphincteric injury. This tissue sparing translates into reduced post-procedure obstruction and more rapid healing. The bladder neck is also preserved in this procedure, thereby minimizing the potential for incontinence and retrograde ejaculation; side effects associated with existing solutions. Using the TUVOR method, BPH tissue is removed by piercing the urethra with a mechanical debulking device. This device is then used to excise, morsellate and liquefy the prostate adenoma. Irrigating fluid flow into and out of the void created in the adenoma can be used to remove tissue.
Unnecessary trauma, injury and side effects such as impotence are avoided by avoiding exposing surrounding normal tissue structures to unnecessary heat, acoustic shock wave or other energy (as occurs with laser, radio frequency, or ultrasound methods). Furthermore, this mechanical removal of bulk does not rely on the body""s innate ability to remove and remodel diseased or necrotic tissue (i.e., RES, the reticuloendothelial system ) to achieve volume reduction. RES clean up does not lead to actual bulk tissue removal or significant prostate volume reduction, but rather to localized scarring. Another feature of the TUVOR process is the use of biocompatible biodegradable polymers as an adhesive that are inserted into the void created in the adenoma. A balloon inflated in the urethra can be used to compress this void while the polymers bond the surfaces. Alternatively or in addition, the surfaces may be secured using more conventional means such as staples or sutures. The balloon expansion also serves several additional purposes. It helps expel any remaining morsellated tissue from the void. It can help stop any residual bleeding in the void. The balloon also enlarges and reshapes the intra-urethral space, thereby eliminating any obstruction. The bonding polymers may be selected to have additional properties such as the ability to facilitate healing, minimize inflammation, decrease fibrotic response, inhibit adenoma regrowth or other therapeutic benefits.
An important feature of the TUVOR process is the ability to combine a transurethral incision with the intra-prostatic bulk removal. This incision relieves some of the pressure on the adenoma. Combined with bulk removal, the intra-urethral volume can subsequently be maximized.
Outpatient performance of TUVOR without catheterization is made possible by the application of a biodegradable polymer in situ casting to the prostatic urethra. This liner further supports and protects the urethra and peri-urethral tissue during healing. This polymer may also be designed to incorporate additional drug or gene therapies.
Outpatient performance of TUVOR is farther enabled by designing the TUVOR device to be of small circumference to perform the procedure under local anesthesia. The TUVOR device can incorporate the ability to administer local anesthesia or the local anesthesia can be administered prior to use of the device.
The steps involved in the TUVOR Process are summarized as follows:
1. Local anesthesia. A tubular sheath with endoscopic vision capabilities is guided to the prostatic urethra and local anesthesia is injected as needed.
2. Transurethral Incision. One or more longitudinal transurethral incisions are made to enter the main body of the prostate, leaving the urethra largely intact. Incisions are continued down to the capsule of the adenoma for immediate relief of the obstruction.
3. De-bulking and Intra-Prostatic Volume Reduction. Volume reduction is achieved via rapid controlled mechanical tissue excision, morsellation and liquefaction of the obstructive adenoma within the middle and lateral aspects of the prostate, leaving the tissue and much of the vascularity of the urethra and peri-urethral region (normal tissue) intact. This mid and lateral debulking preserves the urethra, further reducing the propensity for post-procedure outflow obstruction, pain and further speeds healing.
4. Intra-prostatic void exclusion and space filling with adhesive and/or therapeutic polymers. Voids created as a result of intra-gland xe2x80x9cshelling outxe2x80x9d are filled with adhesive polymers that facilitate intraprostatic void cavity wall bonding and healing. Polymers are specifically selected to minimize inflammation, secondary bleeding and late fibrotic scarring.
5. Endourethral compression and prostatic mass reshaping. The prostatic urethra is further remolded and re-shaped via endourethral balloon inflation, compacting the residual prostatic xe2x80x9cshellxe2x80x9d of tissue and further facilitating bonding and adhesion of intra-gland residual surfaces. The net result is a smaller prostate volume with a larger endourethral lumen and cross-sectional area facilitating urine flow and preserving the urethral lining.
6. Endourethral Polymer Liner Layer. As a final step, a biodegradable polymer liner layer can be applied to the prostatic urethra by in situ casting. This liner is formed from structurally supportive, yet eventually biodegradable polymers. This liner further bolsters and supports the urethra and peri-urethral tissue during healing, eliminating the need for post-procedure catheter drainage. This step may be optional in specific clinical circumstances. It may also be replaced by use of commonly used urethral stents or catheters in specific circumstances.
Depending on the type and severity of the BPH, the steps in the above process may be ordered differently and even selectively performed. This process provides a more biocompatible, less traumatic means of reducing BPH obstruction that is more sparing of normal urethral tissue and physiologic function. Further, TUVOR provides a simple, and effective outpatient procedure for the long-term treatment of BPH.